Class: Oga::XPath::Lexer Private

Inherits:
Object
  • Object
show all
Defined in:
lib/oga/xpath/lexer.rb

Overview

This class is part of a private API. You should avoid using this class if possible, as it may be removed or be changed in the future.

Lexer for turning XPath expressions into a set of tokens. Tokens are returned as arrays with every array having two values:

  1. The token type as a symbol
  2. The token value or nil if there is no value

Basic usage of this lexer is as following:

lexer  = Oga::XPath::Lexer.new('//foo/bar')
tokens = lexer.lex

Alternatively you can stream tokens instead of returning them as a whole:

lexer = Oga::XPath::Lexer.new('//foo/bar')

lexer.advance do |type, value|

end

Unlike the XML lexer the XPath lexer does not support IO instances, it can only lex strings.

Thread Safety

This class keeps track of an internal state. As a result it’s not safe to share a single instance between multiple threads. However, you’re free to use separate instances per thread as there is no global (= class level) shared state.

Constant Summary collapse

AXIS_MAPPING =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future.

Maps certain XPath axes written in their short form to their long form equivalents.

Returns:

  • (Hash)
{
  '@'  => 'attribute',
  '//' => 'descendant-or-self',
  '..' => 'parent',
  '.'  => 'self'
}
AXIS_EMIT_NODE =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future.

Axes that require a separate node() call to be emitted.

Returns:

  • (Array)
%w{descendant-or-self parent self}
AXIS_EMIT_EXTRA_SLASH =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future.

Axes that require an extra T_SLASH token to be emitted.

Returns:

  • (Array)
%w{descendant-or-self}

Class Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ Lexer

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns a new instance of Lexer

Parameters:

  • data (String)

    The data to lex.



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# File 'lib/oga/xpath/lexer.rb', line 1991

def initialize(data)
  @data = data
end

Class Attribute Details

._xpath_lexer_eof_transObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 1922

def _xpath_lexer_eof_trans
  @_xpath_lexer_eof_trans
end

._xpath_lexer_from_state_actionsObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 1897

def _xpath_lexer_from_state_actions
  @_xpath_lexer_from_state_actions
end

._xpath_lexer_index_offsetsObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 126

def _xpath_lexer_index_offsets
  @_xpath_lexer_index_offsets
end

._xpath_lexer_indiciesObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 151

def _xpath_lexer_indicies
  @_xpath_lexer_indicies
end

._xpath_lexer_key_spansObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 101

def _xpath_lexer_key_spans
  @_xpath_lexer_key_spans
end

._xpath_lexer_to_state_actionsObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 1872

def _xpath_lexer_to_state_actions
  @_xpath_lexer_to_state_actions
end

._xpath_lexer_trans_actionsObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 1842

def _xpath_lexer_trans_actions
  @_xpath_lexer_trans_actions
end

._xpath_lexer_trans_keysObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 41

def _xpath_lexer_trans_keys
  @_xpath_lexer_trans_keys
end

._xpath_lexer_trans_targsObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 1812

def _xpath_lexer_trans_targs
  @_xpath_lexer_trans_targs
end

.xpath_lexer_en_mainObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 1960

def xpath_lexer_en_main
  @xpath_lexer_en_main
end

.xpath_lexer_errorObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 1955

def xpath_lexer_error
  @xpath_lexer_error
end

.xpath_lexer_first_finalObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 1951

def xpath_lexer_first_final
  @xpath_lexer_first_final
end

.xpath_lexer_startObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.



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# File 'lib/oga/xpath/lexer.rb', line 1947

def xpath_lexer_start
  @xpath_lexer_start
end

Instance Method Details

#advance(&block) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Advances through the input and generates the corresponding tokens. Each token is yielded to the supplied block.

Each token is an Array in the following format:

[TYPE, VALUE]

The type is a symbol, the value is either nil or a String.

This method stores the supplied block in @block and resets it after the lexer loop has finished.

See Also:

  • Oga::XPath::Lexer.[[#add_token]


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# File 'lib/oga/xpath/lexer.rb', line 2022

def advance(&block)
  @block = block

  data  = @data # saves ivar lookups while lexing.
  ts    = nil
  te    = nil
  stack = []
  top   = 0
  cs    = self.class.xpath_lexer_start
  act   = 0
  eof   = @data.bytesize
  p     = 0
  pe    = eof

  _xpath_lexer_eof_trans          = self.class.send(:_xpath_lexer_eof_trans)
  _xpath_lexer_from_state_actions = self.class.send(:_xpath_lexer_from_state_actions)
  _xpath_lexer_index_offsets      = self.class.send(:_xpath_lexer_index_offsets)
  _xpath_lexer_indicies           = self.class.send(:_xpath_lexer_indicies)
  _xpath_lexer_key_spans          = self.class.send(:_xpath_lexer_key_spans)
  _xpath_lexer_to_state_actions   = self.class.send(:_xpath_lexer_to_state_actions)
  _xpath_lexer_trans_actions      = self.class.send(:_xpath_lexer_trans_actions)
  _xpath_lexer_trans_keys         = self.class.send(:_xpath_lexer_trans_keys)
  _xpath_lexer_trans_targs        = self.class.send(:_xpath_lexer_trans_targs)

  
# line 2048 "lib/oga/xpath/lexer.rb"
begin
	testEof = false
	_slen, _trans, _keys, _inds, _acts, _nacts = nil
	_goto_level = 0
	_resume = 10
	_eof_trans = 15
	_again = 20
	_test_eof = 30
	_out = 40
	while true
	if _goto_level <= 0
	if p == pe
		_goto_level = _test_eof
		next
	end
	if cs == 0
		_goto_level = _out
		next
	end
	end
	if _goto_level <= _resume
	case _xpath_lexer_from_state_actions[cs] 
	when 11 then
# line 1 "NONE"
		begin
ts = p
		end
# line 2076 "lib/oga/xpath/lexer.rb"
	end
	_keys = cs << 1
	_inds = _xpath_lexer_index_offsets[cs]
	_slen = _xpath_lexer_key_spans[cs]
	_wide = ( (data.getbyte(p) || 0))
	_trans = if (   _slen > 0 && 
			_xpath_lexer_trans_keys[_keys] <= _wide && 
			_wide <= _xpath_lexer_trans_keys[_keys + 1] 
) then
			_xpath_lexer_indicies[ _inds + _wide - _xpath_lexer_trans_keys[_keys] ] 
		 else 
			_xpath_lexer_indicies[ _inds + _slen ]
		 end
	end
	if _goto_level <= _eof_trans
	cs = _xpath_lexer_trans_targs[_trans]
	if _xpath_lexer_trans_actions[_trans] != 0
	case _xpath_lexer_trans_actions[_trans]
	when 19 then
# line 166 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_SLASH) 		end
	when 35 then
# line 279 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_ADD) 		end
	when 13 then
# line 1 "NONE"
		begin
te = p+1
		end
	when 12 then
# line 350 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
		end
	when 9 then
# line 332 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
 begin 
    emit(:T_TYPE_TEST, ts, te - 2)
   end
		end
	when 3 then
# line 344 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
 begin 
    emit(:T_VAR, ts + 1, te)
   end
		end
	when 2 then
# line 223 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
 begin 
    emit(:T_STRING, ts + 1, te - 1)
   end
		end
	when 8 then
# line 244 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
 begin 
    emit(:T_AXIS, ts, te - 2)
   end
		end
	when 21 then
# line 255 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
 begin 
    value = AXIS_MAPPING[slice_input(ts, te)]

    add_token(:T_AXIS, value)

    # Short axes that use node() as their default, implicit test. This is
    # added on lexer level to make it easier to handle these cases on
    # parser/evaluator level.
    if AXIS_EMIT_NODE.include?(value)
      add_token(:T_TYPE_TEST, 'node')

      if AXIS_EMIT_EXTRA_SLASH.include?(value) and te != eof
        add_token(:T_SLASH)
      end
    end
   end
		end
	when 16 then
# line 185 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
 begin 
    emit(:T_IDENT, ts, te)
   end
		end
	when 25 then
# line 350 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 33 then
# line 344 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1; begin 
    emit(:T_VAR, ts + 1, te)
   end
		end
	when 37 then
# line 199 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1; begin 
    value = slice_input(ts, te).to_i

    add_token(:T_INT, value)
   end
		end
	when 38 then
# line 205 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1; begin 
    value = slice_input(ts, te).to_f

    add_token(:T_FLOAT, value)
   end
		end
	when 39 then
# line 255 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1; begin 
    value = AXIS_MAPPING[slice_input(ts, te)]

    add_token(:T_AXIS, value)

    # Short axes that use node() as their default, implicit test. This is
    # added on lexer level to make it easier to handle these cases on
    # parser/evaluator level.
    if AXIS_EMIT_NODE.include?(value)
      add_token(:T_TYPE_TEST, 'node')

      if AXIS_EMIT_EXTRA_SLASH.include?(value) and te != eof
        add_token(:T_SLASH)
      end
    end
   end
		end
	when 24 then
# line 185 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1; begin 
    emit(:T_IDENT, ts, te)
   end
		end
	when 1 then
# line 350 "lib/oga/xpath/lexer.rl"
		begin
 begin p = ((te))-1; end
		end
	when 7 then
# line 185 "lib/oga/xpath/lexer.rl"
		begin
 begin p = ((te))-1; end
 begin 
    emit(:T_IDENT, ts, te)
   end
		end
	when 4 then
# line 1 "NONE"
		begin
	case act
	when 0 then
	begin	begin
		cs = 0
		_goto_level = _again
		next
	end
end
	when 6 then
	begin begin p = ((te))-1; end

    value = slice_input(ts, te).to_i

    add_token(:T_INT, value)
  end
	when 7 then
	begin begin p = ((te))-1; end

    value = slice_input(ts, te).to_f

    add_token(:T_FLOAT, value)
  end
	else
	begin begin p = ((te))-1; end
end
end 
			end
	when 14 then
# line 167 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_LPAREN) 		end
# line 350 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
		end
	when 15 then
# line 168 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_RPAREN) 		end
# line 350 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
		end
	when 18 then
# line 169 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_COMMA) 		end
# line 350 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
		end
	when 20 then
# line 170 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_COLON) 		end
# line 350 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
		end
	when 22 then
# line 171 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_LBRACK) 		end
# line 350 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
		end
	when 23 then
# line 172 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_RBRACK) 		end
# line 350 "lib/oga/xpath/lexer.rl"
		begin
te = p+1
		end
	when 45 then
# line 278 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_PIPE) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 34 then
# line 279 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_ADD) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 42 then
# line 280 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_EQ) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 32 then
# line 281 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_NEQ) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 40 then
# line 282 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_LT) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 43 then
# line 283 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_GT) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 41 then
# line 284 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_LTE) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 44 then
# line 285 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_GTE) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 28 then
# line 295 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_AND) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 31 then
# line 296 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_OR) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 29 then
# line 297 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_DIV) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 30 then
# line 298 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_MOD) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 26 then
# line 299 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_MUL) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 27 then
# line 300 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_SUB) 		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
te = p
p = p - 1;		end
	when 17 then
# line 1 "NONE"
		begin
te = p+1
		end
# line 349 "lib/oga/xpath/lexer.rl"
		begin
act = 1;		end
	when 5 then
# line 1 "NONE"
		begin
te = p+1
		end
# line 199 "lib/oga/xpath/lexer.rl"
		begin
act = 6;		end
	when 6 then
# line 1 "NONE"
		begin
te = p+1
		end
# line 205 "lib/oga/xpath/lexer.rl"
		begin
act = 7;		end
	when 36 then
# line 1 "NONE"
		begin
te = p+1
		end
# line 279 "lib/oga/xpath/lexer.rl"
		begin
 add_token(:T_ADD) 		end
# line 199 "lib/oga/xpath/lexer.rl"
		begin
act = 6;		end
# line 2474 "lib/oga/xpath/lexer.rb"
	end
	end
	end
	if _goto_level <= _again
	case _xpath_lexer_to_state_actions[cs] 
	when 10 then
# line 1 "NONE"
		begin
ts = nil;		end
# line 1 "NONE"
		begin
act = 0
		end
# line 2488 "lib/oga/xpath/lexer.rb"
	end

	if cs == 0
		_goto_level = _out
		next
	end
	p += 1
	if p != pe
		_goto_level = _resume
		next
	end
	end
	if _goto_level <= _test_eof
	if p == eof
	if _xpath_lexer_eof_trans[cs] > 0
		_trans = _xpath_lexer_eof_trans[cs] - 1;
		_goto_level = _eof_trans
		next;
	end
	end

	end
	if _goto_level <= _out
		break
	end
end
	end

# line 118 "lib/oga/xpath/lexer.rl"

  # % fix highlight
ensure
  @block = nil
end

#lexArray

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Gathers all the tokens for the input and returns them as an Array.

Returns:

  • (Array)

See Also:

  • Oga::XPath::Lexer.[[#advance]


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# File 'lib/oga/xpath/lexer.rb', line 1999

def lex
  tokens = []

  advance do |type, value|
    tokens << [type, value]
  end

  return tokens
end